Balers, both large and small, for forming parallelepiped bales typically use a needle assembly including a plurality of needles, cantilever-mounted to a transverse support member, to deliver twine through the bale chamber between adjacent ends of a just finished bale and starting bale to respective knotter mechanisms of a knotter assembly to complete the tie cycle on the finished bale and to start the next. Each of the needles must be accurately positioned at the top of its cycle in order to correctly place the twine in the associated knotter mechanism located on the opposite side of the bale chamber from the area occupied by the needles when the latter are in their at rest or standby position. The support member for the needles is typically mounted for swinging through an arc to move the needles as a unit. In addition to each of the needles having to be properly positioned for placing the twine into the associated knotter mechanism, needle position is also critical as the needles move through the arc because of the close proximity of baler components through which they must pass, e.g., the bale chamber floor and top, the plunger face, and the knotter assembly.
On large balers, the cantilever connection of each needle is typically through a clamp arrangement. This can consist of two clamp segments that are clamped around a round tube. The length of the tube is perpendicular to the direction of travel of the needle mechanism during the tie cycle. One clamp segment is welded to the tube while the other defines an inner end of a needle. Each clamp segment has a generally semi-cylindrical surface sized to mate with the tube outer surface. The clamp segments each extend around less than half the circumference of the tube which leaves a space between the clamp segments when they are in position so that the clamp segment defining the inner end of the needle can be rotated relative to the tube. Four bolts, one on each corner of a given clamp arrangement, are used to force the clamp against the tube to provide the desired clamping force. The fore-and-aft position of the needle tip can be adjusted by loosening the two bolts at one end of the clamp arrangement and tightening the opposite pair to rotate the needle clamp segment slightly around the clamp tube. Side-to-side needle tip adjustments however cannot be made in this fashion because the clamp-to-tube contact is solid in this direction. Heretofore, side-to-side needle tip adjustments have been made by physically bending each needle until it is correctly positioned.
The problem to be solved then is how to construct a needle clamping arrangement so as to permit side-to-side needle adjustments as well as fore-and-aft adjustments.